1. Field of the Invention
The present invention relates to a resistor layout technology. More particularly, the present invention relates to a resistor layout technology, which uses metals as a supporting structure to make the thickness of the resistor more uniform.
2. Description of Related Art
As well-known to the common people, the printing technology is one of the oldest inventions in China. However, in the current electronic industry, many printing technologies are applied to manufacture the electronic products. For example, the printing technology is used to manufacture resistor elements.
The conventional resistor printing technology can be divided into stencil printing technology and screen printing technology. For the stencil printing technology, firstly, the molding technology is used to manufacture a stencil with a hollow resistor configuration. Next, the resistor lump (or called resistance paste) is coated on the stencil to manufacture a resistor. The advantage of the stencil printing technology lies in that the manufactured resistor has a fixed shape and the resistance variability of the resistor is relatively small. However, the resistor manufactured through the stencil printing technology has two serious disadvantages. The first one is that the manufacturing cost of the resistor is quite high, and the other is that the variability of the design and the application of the resistor are not flexible. Therefore, recently, each manufacturer usually uses the screen printing technology.
In the screen printing technology, a scraper is used to scrape the resistor lump positioned on the cloth. The resistor lumps are printed on the substrate through small meshes on the screen. The shape of the resistor depends on the distribution of the resistor lumps on the screen, and thus, during the circuit design, the suitable resistor is designed according to the layout design. In addition, when it is required to correct the circuit layout, merely the screen is replaced to perform the process, without necessarily remolding, so as to greatly improve the time effectiveness for the mass production of the product. Therefore, the screen printing technology has the advantages of high design flexibility, low cost, easy transportation, higher throughput, and environmentally friendly, etc.
However, the screen printing technology has a disadvantage, that is, when the scraper scrapes the screen to perform the screen printing, the central part of the screen is more severely affected by the stress of the scraper than those of other parts, so that the screen is bent and deformed. Therefore, the stress forced on the central part of the resistor lump printed on the substrate surface is greater than that of the two sides, and as a result, the central part of the resistor lump is recessed. In addition, the higher the length ratio of the resistor is, the more serious the recess situation of the resistor is, and the higher the resistance variability of the resistor is. When the resistors with defects are applied to a passive attenuator, a matched terminal load, or other systems, it easily causes that each apparatus or each system cannot be normally operated.
In order to solve the recessing problem of the resistor, U.S. Pat. No. 6,187,372 provides an auxiliary structure disposed under the screen printed resistor to solve the above problem. However, as for the resistor manufactured by the method, not only the thickness of the resistor is still not uniform, but the variability of the resistor is also quite high. The reason lies in that a supporter is disposed under the central position of the resistor, such that the thickness of the resistor at the central position is not the same as that of the two sides, and the sectional area of the resistor is reduced. As a result, the resistance of the resistor is increased, and it is difficult to accurately evaluate the resistance of the resistor.
In addition, U.S. Pat. No. 7,038,571 provides a method of using a lateral-wing metal auxiliary structure to reduce the recessing situation of the resistor. However, when the method is used to manufacture a resistor with a high length ratio, the resistor layout design is quite difficult. Besides, the wing metal auxiliary structure used in the method occupies the circuit area.
In view of the above, each manufacturer exerts their effect to seek for a suitable solution to overcome the above problem.